* Say hello to the KDevelop codemodel generator, kdev-cmg.
It produces those subject-to-be-changed codemodels like
the current C++ one (which is provided in examples/cpp)
and uses kdevelop-pg as internal parser ;)

* In order to get both programs into one directory
(they share the need for kdev-pg's includes/ directory,
and it's cool to have all examples/ in one place)
kdev-pg is moved from src/ to kdev-pg/,
and kdev-cmg gets its own kdev-cmg/ directory.

* Refining kdev-pg's serialization visitor:
- it deserves to be written to a seperate file,
lang_serialize_visitor.h, which is created by passing
the --serialize-visitor command line option to kdev-pg.
- fix the "startrule is hardcoded" bug
- don't serialize ast_node.kind, it's not needed